Note: Descriptions are shown in the official language in which they were submitted.
CA 02607345 2007-10-22
METHOD FOR REMOVAL OF PARTICULATE MATTER
Background
[0001) The present invention is related to an improved process for removal of
particulate
matter having airborne potential. More particularly, the present invention is
related to the
application of non-reactive foam to particulate matter for removal wherein the
adhesive readily
adheres to the particulate matter and prohibits dislodged particles from
becoming airborne.
[0002] The removal of materials from areas such as houses, buildings, and
construction
sites is often dangerous. If the material contains particulate matter, or
particulate matter is near
the material being removed, the particulate matter may become airborne. If the
particulate
matter is airborne, it may be inhaled by the material remover or anyone
located near the
removal site and become lodged in that person's nose, eyes, throat or lungs.
Particulate matter
is often defined as a small discrete mass of solid or liquid matter which may
become airborne.
Examples of particulate matter include mold spores and asbestos particles.
[0003] The presence of mold can create extremely hazardous conditions. Mold is
typically a
fungus that produces a superficial growth on various kinds of damp or decaying
organic matter.
Common molds include Aspergillus, Stachybotrys, Cladosporium, Fusarium,
Penicillium, and
Mycotoxins. These species of molds maintain varying health effects on humans,
and any
excessive mold growth can lead to increased allergies, toxicity, and
house/building structural
problems.
[0004] When mold is present, it is comprised of tiny spores of particulate
matter which
reproduce. These tiny spores waft through the air upon the smallest amount of
movement, and
when the mold spores land on damp spots, these mold spores begin growing and
digesting
whatever they are growing on in order to survive. Mold growth often occurs and
becomes
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particularly troublesome when excessive moisture or water accumulates and
remains
undiscovered or un-addressed for long periods of time.
[0005] There are several health effects and symptoms associated with mold
exposure.
Some health effects and symptoms include allergic reaction, asthma, eye
irritation, nasal
stuffiness, wheezing, and skin irritation. More severe reactions are often
indicated with people
who have serious allergies to mold, people with chronic lung illnesses, and
workers who are
exposed to large amounts of mold in occupationai settings. These severe
reactions may
include fever, shortness of breath, cancer, and mold infections in the lungs.
f 0006] Because of these health effects, mold removal is necessary whenever
mold is
present. Removal of mold, however, has become a major concern. When mold is
removed
using currently available methods, the persons removing the mold are exposed
to severe health
risks. During cleaning and removal, mold spores will likely be stirred and
become airborne.
Further, the more the structure is disrupted or broken apart, the higher the
propensity for
dusting, a primary means of transportation for mold spores. Persons near these
airbome
spores are more susceptible and at an increased risk of inhaling these
dislodged particles;
therefore, before clean up and mold removal is begun, it is critical that
measures be taken to
minimize dust and prevent the mold spores from spreading to other areas of the
house or
building. To minimize the particulate matter and prevent spreading of the mold
spores, the area
being cleaned must be properly contained prior to removal.
[0007] Current methods to remediate such mold problems may be expensive and
structurally intrusive. In some cases, it may be necessary to remove and
replace materials that
have been sufficiently invaded with the mold. There have been many reports of
techniques for
the removal of mold. Common techniques include utilizing a form of sanding,
scraping, or dry
ice blasting the mold away. These techniques are extremely difficult and
costly to implement
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but have been a method of choice for many applications. Further, these
techniques often cause
the mold to become airborne and therefore, are hazardous to the persons in the
area and do not
guarantee complete mold removal unless the area is fully contained prior to
removal. Other
techniques have been discussed wherein chemicals are applied to the mold for
removal or
containment. These techniques, however, are also lacking. Bleaches are often
used to contain
or kill mold, such as those found in U.S. Pat. No. 5,783,550; however, bleach
does not remove
the mold and a discoloration usually appears on the mildewed surface treated
with the bleach.
Acids are also frequently used with bleaches to kill and remove the mold.
While acids may be
used, such as those discussed in U.S. Pat. No. 4,097,395 which enable the
remover to dissolve
and remove the mold to produce a visibly clean surface, an irritating odor is
often created.
Further, the difficulty of utilizing strong acid solutions and bleaches in a
closed environment
would be readily realized to one of skill in the art. It would especially be
apparent that the strong
acid necessary to kill and remove mold from a large area would create an
additional hazard to
persons in the area and require a substantial volume of hazardous solvent.
Mold inhibitors with
anti-fungal or anti-microbial agents integrated within a matrix, such as those
found in U.S. Pat.
No. 6,939,937, are also used upon targeted area which require either
remediation or prevention
of growth of fungus or microbes.
[0008] Similar to the removal of mold particulate matter, the removal and
presence of
asbestos particulate matter in an area can also create extremely hazardous
conditions. For
many years asbestos was a material of choice within the building industry as a
sound and
thermal insulator. The properties of asbestos are well documented and further
elaboration is
not necessary herein. One problem with asbestos is the propensity for
dislodged particulate
matter to become airborne wherein it becomes susceptible to being inhaled by
occupants of the
building. After many years it was determined that the inhaled particles can be
detrimental to
ones health and, in fact, the disease created by inhalation of asbestos is now
commonly
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referred to as asbestosis. Unfortunately, by the time the hazards of asbestos
were discovered,
it was the predominant material in such diverse applications as pipe wrap,
flooring material, wall
material, and bulk insulation just to name a few.
[0009] Safety procedures to protect people working in areas containing
asbestos are known
in the art. For example, procedures exist for drilling small holes into
plaster wall containing
asbestos. One such method includes the use of a drill with a vacuum attachment
and a baffle
attachment. Shaving cream is sprayed over the drilling area and the baffle is
fitted over the
shaving cream to control the release of asbestos fibers into the air during
drilling. While this
method is sufficient for drilling small holes, it is insufficient for drilling
in or removal of asbestos
areas larger than the size of a baffle. Further, workers are required to wear
respirators and
protective clothing at all times during the drilling. Because the mere
presence of asbestos
particulate matter is a hazard and working in asbestos containing areas is
difficult, easier and
safer solutions for dealing with asbestos have been contemplated.
[0010] Those of skill in the art are left with two solutions for dealing with
asbestos neither of
which is totally satisfactory. One solution is to contain the particles and
the other is to remove
the asbestos or asbestos containing material. There are many teachings related
to permanent
sealants for asbestos containing materials. These clearly are advantageous
when the
asbestos is to be left in place. Removing the asbestos has proven to be a
substantial problem
since virtually any removal process involves abrading the asbestos thereby
increasing the rate
at which particles are dislodged. The more the structure is disrupted, or
broken apart, the
higher the propensity for dusting. Even sealed asbestos is eventually removed;
therefore, the
removal process occurs for virtually all asbestos containing products.
[0011] There have been many reports of techniques for the safe removal of
asbestos.
These can be broadly characterized as mechanical techniques and chemical
techniques.
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Mechanical techniques utilize some form of area containment in combination
with a pressure
differential or flowing medium to either contain the particles or entrain them
in the stream of
flowing medium. These techniques are extremely difficult and costly to
implement but have
been the method of choice for most applications.
[0012] Chemical techniques have been discussed wherein the asbestos is either
chemically
modified or coated prior to removal. These techniques are also lacking. Acids,
and particularly
fluorides, are known to convert asbestos to a non-asbestos material. Chemical
modification of
the asbestos has been exploited in various forms as illustrated in U.S. Pat.
Nos. 6,589,156;
5,743,841; 5,516,973 and 5,439,322. The difficulty of utilizing strong acid
solutions in a closed
environment would be readily realized to one of skill in the art. It would
especially be apparent
that a stoichiometric volume of a strong acid necessary to remove asbestos
from a large area
would create an additional hazard and require a substantial volume of solvent.
[0013] Various efforts have been reported for coating the asbestos prior to
removal. U.S.
Pat. No. 4,857,085 teaches vaporization of cyanoacrylate to form a hard film
on the asbestos
prior to dismantling the asbestos. This technique is adequate for
encapsulating the visible
surface of the asbestos, but it is not sufficient to cover areas which break
during removal.
Therefore, a hard film is inadequate to solve the problems associated with
airborne particles.
[0014] U.S. Pat. No.4,693,755 describes formation of a cellulosic polymer
which is applied
to the asbestos. The cellulosic polymer is allowed to penetrate, and the
asbestos is removed
while still wet. This technique has an advantage in that the polymer is
somewhat mobile but it is
still inferior for covering newly exposed areas of the asbestos. Furthermore,
the problems
associated with large volumes of solvent remain.
[0015] In summary, the art has been seeking a method for safe complete removal
of
particulate matter which does not require large volumes of solvent, adequately
protects surfaces
CA 02607345 2007-10-22
as they become exposed, prevents persons from inhaling the airbome particles,
and which is
economical.
Summary of the Invention
[0016] It is an object of the present invention to provide a system for
removal of particulate
matter which may become airborne.
[0017] It is an object of the present invention to provide a system for
removal of particulate
matter which may become airbome such as mold spores and asbestos particles.
[00181 It is another object of the present invention to provide a system for
removal of
particulate matter which adequately covers newly exposed particulate matter
resulting from a
removal process.
[0019] Yet another object of the present invention is to provide a system for
removal of
particulate matter which eliminates solvents thereby substantially reducing
the total volume of
material which must be cleaned after removal of the particulate matter.
[0020] A particular feature of the present invention is the ability to utilize
materials which are
safe to handle, readily available, easily dispensed and economical.
[0021] These and other advantages, as will be realized, are provided in an
improved
process for removal of particulate matter. The process includes applying a
foam to the
particulate matter. The particulate matter is then removed, prior to the foam
draining, and
encased in a storage device.
[0022] Yet another embodiment is provided in a process for removal of
particulate matter
from a support structure. The process includes applying a non-reactive foam to
the particulate
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matter and separating the particulate matter from the support structure prior
to the foam
draining.
[0023] Yet another embodiment is provided in a process for removal of
particulate matter
from a support structure. The process includes applying a foam to the
particulate matter
wherein the foam has a pH of 5 to 9. The particulate matter is separated from
the support
structure, prior to the foam draining, and encased in a storage device.
Brief Description of the Figures
[0024] Fig. 1 illustrates the application of foam to a surface.
[0025] Fig. 2 illustrates the separation of a subsection from a surface.
[0026] Fig. 3 illustrates the partial removal of a subsection area from a
larger area.
[0027] Fig. 4 illustrates a removed subsection area and remaining larger area.
Detailed Descrig)tion of the Invention
[0028] The present invention is specific to the use of foam which is applied
to particulate
matter for removal. When particulate matter or material containing particulate
matter, such as
mold infested materials or asbestos, is to be removed, the foam is applied to
the particulate
matter area to prevent it from becoming airborne during removal. As the
particulate matter area
is subsectioned or new areas of particulate matter are exposed during removal,
the foam easily
conforms and migrates to newly exposed surfaces. The foam also has the
advantage of
covering a large area with a minimal amount of material. Neither a baffle
attachment nor a
vacuum is necessary to prevent the particulate matter from becoming airborne.
Further,
because the excursion and exposure levels are nearly zero, the persons
removing the
particulate matter are not required to wear respirators or protective
clothing.
[0029] Particulate matter includes small discrete masses of solid or liquid
matter which may
become airborne. Examples of particulate matter include mold spores and
asbestos particies.
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Other types of particulate matter exist and are considered part of the present
invention without
departing from the spirit and scope of the present invention. In many
instances, particulate
matter poses health risk because it may be inhaled and become lodged in a
person's nose,
eyes, throat, or lungs when it becomes airborne. Further, different types of
particulate matter
maintain varying health effects on humans and therefore require quick and safe
removal.
[0030] The invention will be described with reference to the figures forming
an integral non-
limiting part of the instant disclosure.
[00311 For the purposes of the present invention, foam is defined as a non-
reactive
dispersion of a gas or vapor in a liquid. When removing a particulate matter
area, the drain
time, or time required for the foam to decompose into the original liquid and
gas phases, should
be sufficiently long to allow for the particulate matter area to be removed
and transported to a
contained environment without substantial loss of foam.
[0032] A foam production system typically includes a foam precursor, or pre-
foamed liquid,
an expansion gas and equipment capable of combining, mixing, and discharging
the foam.
[0033] The foam precursor is preferably a liquid with a surface tension
sufficiently low to
form a foam. The surface tension is preferably below about 30 dynes/cm and can
be lowered
by incorporation of suitable surfactants. Water based systems are suitable but
organic based
foams are most preferred. The foam preferably has a near neutral pH of around
5-9 and more
preferably around 6-8. The foam is preferably thixotropic with a viscosity
that is shear
dependent. In the absence of shear force, the foam will not flow and can be
stacked or piled to
depth if desired. 1t is most preferred that the foam precursor be
substantially non-reactive with
the particulate matter. While not limited thereto, a particularly preferred
foam is BilMar Foam,
product code 12-530 available from IPC Supply, Inc. of Anderson, SC.
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[00341 The expansion gas can be air, however, other expansion gas systems are
known to
be useful such as low molecular weight hydrocarbons, nitric oxide or carbon
dioxide. Air is
preferred due to the low cost, low toxicity, and the fact that a separate tank
is not necessary. It
is most important that the expansion gas be non-soluble in the foam precursor.
[0035] The foam precursor may have adjuvants as known in the art including
surfactants
such as sodium lauryl sulfate; stick or adhesive additives such as styrene-
butadiene polymer;
thickeners or viscosity modifiers such as typical paint thickeners, gelatin or
modified starches;
and others.
[0036] Foam generating equipment is well documented and not particularly
limiting herein.
The foam generating equipment has two main components. One component combines
the
liquid foam precursor with the expansion gas. The mixing is preferably very
thorough to insure
the drain time is sufficiently long and that the expansion is optimum. The
mixing can be done by
passing through a hose, or pipe, with sufficient flow turbulance to mix the
components.
Alternatively, the mixture can be passed through a mixing device such as a
packed bed mixture.
[0037] During use, if a large area of particulate matter or material
containing particulate
matter requires removal, the particulate matter area to be removed is covered
with foam. A
subsection of the particulate matter area is then typically separated from the
larger section by
cutting or otherwise breaking the particulate matter area into subsections
within the boundary of
the foam covering. Alternatively, the particulate matter area is separated
from a support
structure. The present invention does not contemplate drilling small holes
into the particulate
matter area. One advantage of the foam is that the cutting can occur through
the foam and as
the cutting element is withdrawn, the foam heals thereby maintaining a
continuous coating. As
the subsection is withdrawn, the foam begins to elongate, and, as the foam
breaks, the foam
naturally collapses to cover both exposed edges from the cutting operation.
This ability to
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stretch, heal and collapse over the newly formed edges provides a benefit not
available from
prior art techniques. As would be realized, the particulate matter area is
removed prior to the
foam draining.
[0038] After the particulate matter area is removed, it is preferable to
encase the particulate
matter area in a storage device, such as sealed plastic, to avoid particles
becoming airbome
during transport and delivery. It would be readily apparent that it is most
preferable to encase
the removed particulate matter area prior to the foam draining.
[0039] As discussed above, the foam can easily cover a large area with a
minimal amount
of material. Further, a baffle attachment for covering the foam to prevent the
particulate matter
from becoming airborne is not necessary. A vacuum is also not necessary in the
area because
the foam fully prevents the particulate matter from becoming airborne. Because
the excursion
and exposure levels are nearly zero using the present invention, the persons
removing the
particulate matter are not required to wear respirators or protective
clothing.
[0040] An example of the process of particulate matter removal will be
described with
reference to the figures. In the various figures, similar elements are
numbered accordingly.
[0041] Application of the foam is illustrated in Fig. 1. In Fig. 1, a user, 1,
activates a nozzle,
2, which receives foam precursor and expansion gas from a foam generator, 3,
via a hose, 4.
The foam, 5, is applied to a surface, 6. If the entire surface is to be
removed intact, foam is
applied to the edges of the surface as would be realized from the disclosure
herein. It is most
common to remove a subsection, 7, of the surface, 6, by cutting or otherwise
forming a
separation between the surface and the subsection. A rotary tool, 8, is
particularly suitable for
cutting the subsection from the surface as illustrated in Fig. 2. As the
rotary tool enters and is
withdrawn, the foam extends and then collapses and heals providing a near
continuous seal
before, during, and after the cutting operation.
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[0042] A subsection partially removed from the surface is illustrated in Fig.
3. As the
subsection is removed, the foam, 5, elongates and, due to the thixotropic
properties, eventually
collapses thereby covering the edge of the subsection, 9, and the edge of the
surface, 10,
illustrated in Fig. 4. The user would then continue to apply foam to a second
subsection for
separation from the surface.
[0043] Those skilled in the art will realize that the foam may be applied to
any particulate
matter containing surface or area, including support structures such as the
wall, the floor, and
the ceiling. If the particulate matter is being removed from the floor, a
particularly preferred
embodiment of the process includes the use of a shovel type device. After the
foam is applied
to the removal area, the shovel type device is used to breakup the particulate
matter containing
material. As the particulate matter containing material is broken up, the foam
elongates and
collapses to cover the newly exposed portion of the material. The shovel type
device may also
be used to collect and transport the particulate matter containing material
into a storage device
for disposal.
[0044] The invention has been described with particular emphasis on the
preferred
embodiments without limit thereto. Based on the foregoing description, other
embodiments and
alterations would be apparent without departing from the scope of the
invention which is more
specifically set forth in the claims appended hereto.
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